1. Field of the Invention
The present invention relates to oil well fire suppression devices and more particularly to a portable, self contained fire suppression device serving the dual purposes of extinguishing an oil well fire and thereafter sealing the well against further leakage and re-ignition.
2. Background
In the recent Gulf war, Iraqi forces ignited over 600 oil wells in an effort to eliminate Kuwait""s oil infrastructure. The conflagration lasted from February 1991 until Nov. 6, 1991. During this period it is estimated that the daily loss of oil and natural gas was between 4-6 million barrels and 100 million cubic meters respectively.
The two major problems encountered by firefighters in Kuwait were lack of equipment and lack of water. Cranes to lift the wellheads, backhoes to dig around the wellheads, dozers to build roads and move debris and equipment to fight the fires were in short supply and desperately needed for the firefighting to begin in earnest. Existing pipelines used to carry oil from gathering stations in the oilfields to the Persian Gulf were reversed to carry saltwater from the Gulf back to the oilfields to fight the fires. The logistical problems involved in pumping the 1.5 billion gallons of water that was eventually used to fight the fires slowed the flow of water to a trickle.
It was discovered that extinguishing the fire was not the most difficult part of well control. It""s what is done after the fire is out that is dangerous. As long as the well is blowing, there is a possibility the well could flash and re-ignite, injuring or killing everyone on location. This dangerous potential is why one can""t wait for water, or to borrow equipment from the next location. Everything has to be in place to cap the well once the fire is out. The less time spent capping the well after the fire is out, the less likely someone gets hurt.
Prior art methods for extinguishing well fires utilized vast quantities of water or explosive charges to snuff out the fire after which the well had to be approached for capping. Approaching the well was often complicated by the build-up of coke around the site which required excavation to be carried out in dangerous proximity to the gushing well. The risks are obvious.
The present invention is deployed using a large bulldozer such as a Caterpillar D11. The unit is attached to a hydraulically controlled frame mounted to the front of the bulldozer. The unit can be raised and lowered in order to position it over the well fire.
The unit operator is protected within a protective cab equipped with air conditioning, window cleaning systems, two-way radio communications, and an emergency escape plan/egress system.
In a preferred embodiment the present invention provides a portable, self contained containment device for extinguishing oil well fires. It is a primary objective of the device to be able to rapidly deploy to a well fire site and, with a minimum of logistical preparation consisting simply of filling tanks within the containment device, and positioning it over the fire.
It is a further object of the invention to construct the containment vessel in a manner which utilizes well known principles of science to physically contain and extinguish the fire within seconds, channel and control escaping oil and gas, and plug the well with a removable bladder. The bladder being capable of withstanding well head pressures up to 800 psi. such as those found in wells in the Middle East
It is a further object of the invention to use escaping oil to cool the containment vessel and well head environment.
It is a further object of the invention to use heat activated valves to release liquid nitrogen into the fire column to use the force of the fire to suck the nitrogen into the flame thereby assisting to extinguish it.
It is a further object of the invention to follow a sequence of deployment as follows;
1. Fill a water containment cylinder
2. Fill Nitrogen tanks
3. Open oil and gas escapement valves
4. Add sand to the leveling box to equalize weight
5. Approach vessel with lifting equipment
6. Raise containment vessel to 12xe2x80x3 above well head keeping the bottom of the vessel below the flames.
7. (If necessary) Proceed to the well at the direction of two spotters
8. Lowering the vessel in place once it is over the well casing. (It need not be perfectly centered)
9. Using the deployment vehicle as additional ballast to keep the vessel in place adds a further 203,000 pounds to the initial weight of the vessel (38,000 pounds.)
It is a further object of the invention to follow the above deployment sequence to initialize the extinguishment/containment sequence;
1. Cessation of oxygen to the flame
2. Heat activated nozzles release nitrogen
3. Perforated internal baffles break oil down
4. Flame is extinguished in 5-8 seconds
5. Vessel begins to fill with oil aiding cooling of the vessel
6. Gas release valve is slowly closed forcing remaining energy and flow of oil through the oil release valve
7. Once oil temperature is reduced sufficiently, oil release valves are slowly closed. Oil is now contained.
8. Expandable bladder is inserted into the well casing to restrict the flow of oil and gas.
9. With the bladder in place approximately 10xe2x80x2 to 20xe2x80x2 into the casing, the top of the bladder shaft can be removed, the oil drained from the vessel which can then be removed.
10. A xe2x80x9cChristmas treexe2x80x9d manifold is fitted to the well casing providing a second valve containment means
11. Pressure is released from the bladder which is then raised above the level of the Christmas tree valve. Once it is above the level of the lower valve, it can be closed to complete the containment process.
Utilizing a vehicle such as a Caterpillar D11, a continuous lifting beam is attached to each side. The lifting beam extends 30xe2x80x2 from the center pin to the front or lifting section. The beam extends 24xe2x80x2 to the rear of the center pin. Attached to the rear section are a pair of hydraulic cylinders. As the vessel approaches the well, the operator places the containment vessel in place as described. The rear cylinders are then activated and pressed into the ground lifting the bulldozer off the ground thus transferring its weight to the base of the containment vessel.
The following are the general specifications for a first embodiment of the invention;
1. (FIG. 1-12) Water containment Cylinder (1) 10xe2x80x2 diameter, 10xe2x80x21xe2x80x3 high with a wall thickness of xc2xdxe2x80x3 steel. Approximate weight 6,444 lbs. Purpose: to provide ballast, will contain approximately 13,000 lbs of water which will also serve as coolant.
2. (FIG. 1-21) Oil containment Vessel (1) 15xe2x80x2 high, 5xe2x80x2 diameter, wall thickness 1xe2x80x3 steel, approximate weight 9,525 lbs. Purpose: When placed over the well, it will penetrate the sand, sealing off the oxygen from the bottom. It will then fill with oil becoming as temporary of permanent containment vessel.
3. (FIG. 1-22,22xe2x80x2) Steam relief vents (2) Sizexe2x80x946xe2x80x3 pipe 5xe2x80x2 long. Will release steam from the water containment cylinder.
4. (FIG. 1-41) Primary baffle (1) Size, 5xe2x80x2 diameter cone with flat top plate that has 36 2xe2x80x3 holes. Thicknessxe2x80x941xe2x80x3 plate. Purpose: To reduce the oil from one solid cylinder (column) to 32 individual cylinders thus reducing pressure.
5. (FIG. 1-42) Secondary Baffle (1). Size 5xe2x80x2 diameter 30 degree cone. Thickness xc2xdxe2x80x3 plate with 1xe2x80x3 holes. Purpose: The further reduce oil particle size and thus oil pressure.
6. (FIG. 1-43) Third baffle (1) Size 5xe2x80x2 diameter 15 degree cone. Thickness, xc2xdxe2x80x3 plate with xc2xexe2x80x3 holes. Purpose: Same as second baffle.
7. (FIG. 1-21a) Fourth baffle (1) 5xe2x80x2 diameter plate. Thickness xc2xdxe2x80x3 plate with xc2xdxe2x80x3 holes. Purpose: Same as other baffles.
8. (FIG. 1-18a) Drain for water containment cylinder (4) Size, 4xe2x80x3 pipe with ball valve. Purpose: To drain hot water from the cylinder to allow for cool water to be pumped in.
9. (FIG. 1-24) Gate Valve (1) Sizexe2x80x9412xe2x80x3. Purpose: To control energy being released from fire and well head.
10. (FIG. 1-18a) Horizontal relief and control pipe. Sizexe2x80x948xe2x80x3 pipe. Purpose: Primary purpose is to release pressure in the vessel, the secondary purpose is to control the flow of oil.
11. (FIG. 1-19 one only shown) Gate valves (2) Sizexe2x80x948xe2x80x3. Purpose: To control the flow of oil.
12. (FIG. 1-18b) Check valve (1) Sizexe2x80x948xe2x80x3. Purpose: To prevent the flow of oxygen to the vessel. Will also allow for the flow of oil when required to so do.
13. (FIG. 122,22xe2x80x2) Water Pipe Connection (4) Sizexe2x80x944xe2x80x3 pipe with quick connects. Purpose: To allow the flow of water into the water containment cylinder.
14. (FIG. 1-50,50xe2x80x2) Liquid Nitrogen Cylinder (4) Size 10xe2x80x3-48xe2x80x3. Purpose: To immediately cool the oil vessel while simultaneously extinguishing the fire.
15. (FIG. 1-50a, 50axe2x80x2) Insulation packs (4) Sizexe2x80x944xe2x80x3 mineral wool batt with protective covering. Purpose: To prevent overheating of the nitrogen tanks.
16. (FIG. 121c) Spray foam insulation. Thicknessxe2x80x941xc2xdxe2x80x3. Purpose: To protect the oil vessel wall during flame suppression. Possible productsxe2x80x94Fendolite M-11, Albi clad #800, Pyrocrete 241 or Kaowal Firemaster board.
17. (FIG. 116) Ballast Box. (1) Size 2xe2x80x2xc3x9710xe2x80x2xc3x973xe2x80x3. Wall thicknessxe2x80x94xc2xdxe2x80x3 steel. Purpose: To equalize weight and balance the unit. Can be filled with sand as required.
18. (FIG. 151,52) Nitrogen Piping and Heat controlled nozzles. (4) Sizexe2x80x944xe2x80x3 pipe. Purpose: To transfer Nitrogen from the tank to the vessel, with the nozzles releasing nitrogen at a specified temperature.
20. Ladder for maintenance purposes.
21. (FIG. 330) Motor unit to lower the shaft and bladder into the well casing.
22. (FIG. 392, 47) Shaft and bladder.